1. Technical Field
The present disclosure relates to a method of fabricating a semiconductor device.
2. Description of the Related Art
As one of the scaling technologies to increase the density of semiconductor devices, multi-gate transistor technologies have been suggested, in which silicon bodies in a fin or nano wire shape are formed on a substrate, with gates then being formed on surfaces of the silicon bodies.
Such multi-gate transistors allow easy scaling, as they use a three-dimensional channel. Further, current control capability may be enhanced without increasing gate length of the multi-gate transistors. Furthermore, it is possible to effectively suppress a short channel effect (SCE) which is a phenomenon where the electric potential of the channel region is influenced by a drain voltage.
However, as scale-down of logic products continuously progresses, fine processes are getting more difficult due to increased aspect ratio. For example, an epitaxy process for forming a source/drain (S/D) region is sensitively affected by states of a silicon (Si) surface, and growth of silicon or silicon germanium may not properly be performed when a pre-clean of a silicon recess surface is not sufficiently performed because of modification of the aspect ratio and spacer configuration. The affected growth of silicon or silicon germanium may cause a ‘less defect’. The ‘less defect’ may be a state in which an epitaxial growth of a silicon or a silicon germanium is not sufficient to perform a proper function in a device. For example, a source/drain pattern formed by an epitaxial growth may be smaller than an intended size, and thus may have a “less defect,” also described as an “insufficiency defect.” Because the less defect substantially affects a product yield, ensuring the pre-clean process is important such that the source/drain epitaxial growth is well performed. Ensuring an effective pre-bake process performed immediately before a growth process in an epitaxy chamber is also helpful to get an effective epitaxial growth.